1. Field of the Invention
The present invention relates to a display screen turning apparatus, and more particularly, it relates to a display screen turning apparatus comprising a rotating member mounted with a display screen and rotatable in a horizontal plane.
2. Description of the Background Art
A display screen turning apparatus comprising a rotating member mounted with a display screen and rotatable in a horizontal plane is known in general, as disclosed in Japanese Patent Laying-Open Nos. 2003-74787 and 2005-284087, Japanese Utility Model Laying-Open No. 6-9277 (1994) and Japanese Patent Laying-Open Nos. 7-240890 (1995) and 63-88399 (1988), for example.
The aforementioned Japanese Patent Laying-Open No. 2003-74787 discloses a display screen turning apparatus (rotary stand) comprising a base plate, a coupling plate receiving a display (or an audio system) thereon and rotating with the display and a holding plate holding the coupling plate between the same and the base plate and keeping the coupling plate rotatable in the vertical and horizontal directions. In this display screen turning apparatus (rotary stand), the holding plate, the coupling plate and the base plate are superposed with each other in descending order while threaded bolts and springs (compression springs) are inserted into through-holes linearly passing through the holding plate, the coupling plate and the base plate and tightened by prescribed quantities with nuts, so that the coupling plate receives prescribed pressure contact force from the holding plate and the base plate. In this rotary stand, the coupling plate rotates with the display while producing prescribed frictional force.
The aforementioned Japanese Patent Laying-Open No. 2005-284087 discloses a display screen turning apparatus comprising a base member, a bracket member receiving a thin display thereon and horizontally turning with the thin display and a plate (friction disc) interposed between the base member and the bracket member. In this display screen turning apparatus, the bracket member, the plate and the base member are superposed with each other in descending order while threaded bolts and springs (compression springs) are inserted into through-holes linearly passing through the bracket member, the plate and the base member and tightened by prescribed quantities with nuts, so that the plate receives prescribed pressure contact force from the bracket member and the base member. In this display screen turning apparatus, the bracket member horizontally turns with the thin display while producing prescribed frictional force.
The aforementioned Japanese Utility Model Laying-Open No. 6-9277 discloses a display screen turning apparatus (angle regulator) comprising a bearer, an angle regulating stand receiving a display thereon and rotating with the display and a holding shaft, having a T-shaped section, holding the angle regulating stand between the same and the bearer and keeping the angle regulating stand rotatable in the vertical direction. In this display screen turning apparatus (angle regulator), the angle regulating stand and the bearer are superposed with each other in descending order while the holding shaft is inserted into a through-hole linearly passing through the angle regulating stand and the bearer so that one side of the holding shaft is prevented from downward displacement from the upper surface of the angle regulating stand by the T-shaped section and a spring (compression spring) is inserted into the holding shaft from an end having no T-shaped section and covered with a washer screwed to the holding shaft, whereby the holding shaft having the T-shaped section holds the angle regulating stand and the bearer with prescribed pressure contact force. In this display screen turning apparatus (angle regulator), the angle regulating stand rotates with the display while producing prescribed frictional force between the same and the bearer.
The aforementioned Japanese Patent Laying-Open No. 7-240890 discloses a display screen turning apparatus (cabinet rotator) comprising a base having an arcuate groove, a roller rolling along the arcuate groove and a bottom plate having a cabinet body (display) provided with an arcuate rib on the bottom thereof. In this display screen turning apparatus (cabinet rotator), the arcuate rib formed to be undisplaceable from the arcuate groove of the base moves on the roller rolling along the arcuate groove, thereby horizontally turning the heavy cabinet body on the base.
The aforementioned Japanese Patent Laying-Open No. 63-88399 discloses a display screen turning apparatus (reverser for a surveillance television camera or the like) comprising a circular rotor plate having a rotating shaft directly connected to a surveillance television camera, a roller rotating in contact with a hole whose inner side surface is cut into a C shape in plan view to have a smooth continuous curved surface in this rotor plate, a motor directly connected to the rotating shaft of the roller and a cam mechanism capable of regularly pressing the roller to come into contact with the inner side surface of the rotor plate regardless of the position in contact with the inner side surface of the roller when the roller rotates in contact with the inner side surface of the rotor plate cut into the C shape. In this display screen turning apparatus (reverser for a surveillance television camera or the like), the roller regularly rotates in the same direction through the motor and is regularly in contact with the C-shaped inner side surface of the rotor plate through the cam mechanism, so that the roller rotationally moves along the inner side surface of the rotor plate and the rotor plate repeats rotating while periodically reversing the rotational direction.
According to the aforementioned Japanese Patent Laying-Open No. 2003-74787, however, the conventional display screen turning apparatus (rotary stand) is conceivably assembled by meshing the nuts with the threaded bolts for controlling the shrinkage of the springs (compression springs) so that the coupling plate receives the prescribed pressure contact force from the holding plate and the base plate, to require a step of controlling the pressure contact force (shrinkage of the springs). Thus, the assembling operation is so complicated that it is difficult to improve assembling workability.
According to the aforementioned Japanese Patent Laying-Open No. 2005-284087, the conventional display screen turning apparatus is conceivably assembled by meshing the nuts with the threaded bolts for controlling the shrinkage of the springs (compression springs) so that the plate receives the prescribed pressure contact force from the bracket member and the base member, to require a step of controlling the pressure contact force (shrinkage of the springs). Thus, the assembling operation is so complicated that it is difficult to improve assembling workability.
According to the aforementioned Japanese Utility Model Laying-Open No. 6-9277, the conventional display screen turning apparatus (angle regulator) is conceivably assembled by meshing a nut and the washer with a threaded bolt of the holding shaft having the T-shaped section for controlling the shrinkage of the spring (compression spring) so that the angle regulating stand and the bearer receive the prescribed pressure contact force from the holding shaft having the T-shaped section, to require a step of controlling the pressure contact force (shrinkage of the spring). Thus, the assembling operation is so complicated that it is difficult to improve assembling workability.
In the conventional display screen turning apparatus (cabinet rotator) proposed in the aforementioned Japanese Patent Laying-Open No. 7-240890, the cabinet body (display) is merely placed on the base by coming into contact with the roller arranged in the arcuate groove of the base opposed thereto through the arcuate rib provided on the bottom thereof, and is conceivably easily inclined through abrupt horizontal force, although the same has stability in the vertical downward direction due to its own weight. Therefore, the cabinet may easily jolt during rotation.
In the conventional display screen turning apparatus (reverser for a surveillance television camera or the like) proposed in the aforementioned Japanese Patent Laying-Open No. 7-240890, the roller merely rotates in contact with only the inner side surface (horizontal direction) of the rotor plate, and the display screen turning apparatus is conceivably provided with no mechanism for inhibiting the rotor plate from displacement in the vertical direction (rotational axis direction) following rotation. Therefore, the rotor plate may easily jolt during rotation, depending on the conditions of use.